40 homers, 40 doubles same season done 38 times, including 2 in 2015.

No, not both 2015 MVP, just one of them.  Guess and then look at the complete list below.  Nolan Arenado of Colorado is the non MVP 2015 40/40 guy.

Albert Belle in 1995 became the only 50/50 guy ever: 50 homers, 52 doubles.  Ruth is at the top of the list in homers: 59.  Among the 38 are 11 seasons with at least 50 doubles, led by Klein and Helton with 59 doubles.

Multiple times:
3: Gehrig, Pujols
2: Ruth, Klein, Greenberg, Belle, Helton, Ortiz

Slugging average:
high: Ruth 1921 .846
low: Soriano 2006 .560
six under .600
seven at least .700

League leaders:
14 led in homers.
12 led in doubles.
Leading in both: Hornsby, Greenberg, Stargell, Belle
15 led in SLG.
6 led in BA; Hornsby: .401.
Only Ruth led in SO: 93 in 1923.
2 scored fewer than 100 runs: Ortiz, Arenado.
Greenberg led in RBI: 184.
19, exactly half, led in RBI.
Soriano: only one with fewer than 100 RBI: 95.

OK, the 2015 40/40 MVP: Josh Donaldson, not Bryce Harper (42 homers, 38 doubles).  Pretty close, so Harper was a good guess.

Rk	Player	HR	2B	Year	Age	Tm	Lg	G	PA	AB	R	H	3B	RBI	BB	IBB	SO	HBP	SH	SF	GDP	SB	CS	BA	OBP	SLG	OPS	Pos
1	Babe Ruth	59	44	1921	26	NYY	AL	152	693	540	177	204	16	168	145		81	4	4			17	13	.378	.512	.846	1.359	*78/13
2	Chris Davis	53	42	2013	27	BAL	AL	160	673	584	103	167	1	138	72	12	199	10	0	7	4	4	1	.286	.370	.634	1.004	*3/D
3	Albert Belle	50	52	1995	28	CLE	AL	143	631	546	121	173	1	126	73	5	80	6	0	4	24	5	2	.317	.401	.690	1.091	*7/D
4	Todd Helton	49	54	2001	27	COL	NL	159	697	587	132	197	2	146	98	15	104	5	1	5	14	7	5	.336	.432	.685	1.116	*3/H
5	Albert Belle	49	48	1998	31	CHW	AL	163	706	609	113	200	2	152	81	10	84	1	0	15	17	6	4	.328	.399	.655	1.055	*7/D
6	Larry Walker	49	46	1997	30	COL	NL	153	664	568	143	208	4	130	78	14	90	14	0	4	15	33	8	.366	.452	.720	1.172	*9/3H8D
7	Lou Gehrig	49	40	1934	31	NYY	AL	154	690	579	128	210	6	166	109		31	2	0			9	5	.363	.465	.706	1.172	*3/6
8	Albert Pujols	47	45	2009	29	STL	NL	160	700	568	124	186	1	135	115	44	64	9	0	8	23	16	4	.327	.443	.658	1.101	*3/HD
9	David Ortiz	47	40	2005	29	BOS	AL	159	713	601	119	180	1	148	102	9	124	1	0	9	13	1	0	.300	.397	.604	1.001	*D3/H
10	Lou Gehrig	47	52	1927	24	NYY	AL	155	717	584	149	218	18	173	109		84	3	21			10	8	.373	.474	.765	1.240	*3
11	Alfonso Soriano	46	41	2006	30	WSN	NL	159	728	647	119	179	2	95	67	16	160	9	2	3	3	41	17	.277	.351	.560	.911	*7/H
12	Derrek Lee	46	50	2005	29	CHC	NL	158	691	594	120	199	3	107	85	23	109	5	0	7	12	15	3	.335	.418	.662	1.080	*3
13	Albert Pujols	46	51	2004	24	STL	NL	154	692	592	133	196	2	123	84	12	52	7	0	9	21	5	5	.331	.415	.657	1.072	*3/DH
14	Chipper Jones	45	41	1999	27	ATL	NL	157	701	567	116	181	1	110	126	18	94	2	0	6	20	25	3	.319	.441	.633	1.074	*5/6
15	Juan Gonzalez	45	50	1998	28	TEX	AL	154	669	606	110	193	2	157	46	9	126	6	0	11	20	2	1	.318	.366	.630	.997	*9D/H
16	Miguel Cabrera	44	40	2012	29	DET	AL	161	697	622	109	205	0	139	66	17	98	3	0	6	28	4	1	.330	.393	.606	.999	*5/D3
17	Richard Hidalgo	44	42	2000	25	HOU	NL	153	644	558	118	175	3	122	56	3	110	21	0	9	13	13	6	.314	.391	.636	1.028	*897/H
18	Willie Stargell	44	43	1973	33	PIT	NL	148	609	522	106	156	3	119	80	22	129	3	0	4	6	0	0	.299	.392	.646	1.038	*7/H
19	Mark Teixeira	43	41	2005	25	TEX	AL	162	730	644	112	194	3	144	72	5	124	11	0	3	18	4	0	.301	.379	.575	.954	*3/D
20	Manny Ramirez	43	44	2004	32	BOS	AL	152	663	568	108	175	0	130	82	15	124	6	0	7	17	2	4	.308	.397	.613	1.009	*7D/H
21	Albert Pujols	43	51	2003	23	STL	NL	157	685	591	137	212	1	124	79	12	65	10	0	5	13	5	1	.359	.439	.667	1.106	*73/HD
22	Frank Thomas	43	44	2000	32	CHW	AL	159	707	582	115	191	0	143	112	18	94	5	0	8	13	1	3	.328	.436	.625	1.061	*D3/H
23	Jeff Bagwell	43	40	1997	29	HOU	NL	162	717	566	109	162	2	135	127	27	122	16	0	8	10	31	10	.286	.425	.592	1.017	*3/HD
24	Chuck Klein	43	45	1929	24	PHI	NL	149	679	616	126	219	6	145	54		61	0	9			5		.356	.407	.657	1.065	*98
25	Nolan Arenado	42	43	2015	24	COL	NL	157	665	616	97	177	4	130	34	13	110	4	0	11	17	2	5	.287	.323	.575	.898	*5/H
Rk	Player	HR	2B	Year	Age	Tm	Lg	G	PA	AB	R	H	3B	RBI	BB	IBB	SO	HBP	SH	SF	GDP	SB	CS	BA	OBP	SLG	OPS	Pos
26	Todd Helton	42	59	2000	26	COL	NL	160	697	580	138	216	2	147	103	22	61	4	0	10	12	5	3	.372	.463	.698	1.162	*3/H
27	Shawn Green	42	45	1999	26	TOR	AL	153	696	614	134	190	0	123	66	4	117	11	0	5	13	20	7	.309	.384	.588	.972	*9/H
28	Hal Trosky	42	45	1936	23	CLE	AL	151	671	629	124	216	9	162	36		58	3	3			6	5	.343	.382	.644	1.026	*3/4
29	Rogers Hornsby	42	46	1922	26	STL	NL	154	704	623	141	250	14	152	65		50	1	15			17	12	.401	.459	.722	1.181	*4
30	Josh Donaldson	41	41	2015	29	TOR	AL	158	711	620	122	184	2	123	73	0	133	6	2	10	16	6	0	.297	.371	.568	.939	*5/DH
31	David Ortiz	41	47	2004	28	BOS	AL	150	669	582	94	175	3	139	75	8	133	4	0	8	12	0	0	.301	.380	.603	.983	*D3/H
32	Carlos Delgado	41	57	2000	28	TOR	AL	162	711	569	115	196	1	137	123	18	104	15	0	4	12	0	1	.344	.470	.664	1.134	*3
33	Hank Greenberg	41	50	1940	29	DET	AL	148	670	573	129	195	8	150	93		75	1	3		15	6	3	.340	.433	.670	1.103	*7
34	Lou Gehrig	41	42	1930	27	NYY	AL	154	703	581	143	220	17	173	101		63	3	18			12	14	.379	.473	.721	1.194	*3/7
35	Babe Ruth	41	45	1923	28	NYY	AL	152	697	522	151	205	13	130	170		93	4	3			17	21	.393	.545	.764	1.309	97/83
36	Ellis Burks	40	45	1996	31	COL	NL	156	685	613	142	211	8	128	61	2	114	6	3	2	19	32	6	.344	.408	.639	1.047	*78/H
37	Hank Greenberg	40	49	1937	26	DET	AL	154	701	594	137	200	14	184	102		101	3	2			8	3	.337	.436	.668	1.105	*3
38	Chuck Klein	40	59	1930	25	PHI	NL	156	721	648	158	250	8	170	54		50	4	13			4		.386	.436	.687	1.123	*9

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 11/22/2015.