I was fortunate to get eyedoc to sell me his Pole Position II cockpit sitdown cabinet.  I know he wanted to keep it, but lucky for me his wife wouldn't let him.  

This cabinet was completely gutted except for the steering wheel, shifter, speakers and coin door.  No wires, no monitor, no PCBs, nothing.  So, the decision was what to do with it.  
Pole Position PCBs are notorious for being the worst out there to keep working.  They break easily and generally are not at all hardy.  The only one I could even find didn't even have the standard edge connector and required a special harness.  Restoring this baby to a Pole Position just wasn't realistic.
Sooooooo - IF YOU ARE THE TYPE OF PERSON WHO WOULD THROW THEMSELVES IN FRONT OF AN ONCOMING BULLET TO PREVENT AN ORIGINAL CABINET FROM BEING CONVERTED - you should probably stop reading right now.
My options for this boiled down to MAME or XBOX.  
MAME:  Let's face it, most racing games in MAME are teh suxxorz.  Also making MAME less attractive is the need for both a 360 wheel and 270 wheel.  I don't need another swappable panel cabinet.  A cockpit cabinet is also hard to get inside if you have it stuffed back in the corner of your game room.
XBOX:  Racing games in XBOX are freaking awesome.  If you haven't played a few rounds of BURNOUT 3: TAKEDOWN you have seriously missed out.  Outrun 2006 is also a great, great update to one of my all time favorite arcade classics.  In fact, there are at least 100 great racing games for XBOX; take a look:
1. Burnout 3: Takedown 
2. Project Gotham Racing 2 
3. Forza Motorsport 
4. OutRun 2006: Coast 2 Coast 
5. Burnout Revenge 
6. Rallisport Challenge 2 
7. Burnout 2: Point of Impact 
8. MotoGP 2 
9. Midnight Club 3: DUB Edition Remix 
10. Midnight Club II 
11. Rallisport Challenge 
12. MotoGP 
13. Project Gotham Racing 
14. Colin McRae Rally 3 
15. Colin McRae Rally 04 
16. NASCAR 2005: Chase for the Cup 
17. NASCAR Thunder 2004 
18. Midnight Club 3: DUB Edition 
19. MotoGP 3: Ultimate Racing Technology 
20. TOCA Race Driver 2: The Ultimate Racing Simulator 
21. Need for Speed Most Wanted 
22. TOCA Race Driver 3 
23. Colin McRae Rally 2005 
24. NASCAR Thunder 2003 
25. Need for Speed Underground 
26. Sega GT 2002 
27. Need for Speed Underground 2 
28. Pro Race Driver 
29. The Simpsons: Hit & Run 
30. NASCAR Thunder 2002 
31. F1 2001 
32. Need for Speed: Hot Pursuit 2 
33. MX Unleashed 
34. OutRun2 
35. NASCAR Heat 2002 
36. Midtown Madness 3 
37. Splashdown 
38. MX vs. ATV Unleashed 
39. NASCAR 06: Total Team Control 
40. Mashed 
41. Burnout 
42. MTX Mototrax 
43. Apex 
44. Quantum Redshift 
45. MX Superfly 
46. Test Drive: Eve of Destruction 
47. Rally Fusion: Race of Champions 
48. ATV Quad Power Racing 2 
49. Juiced 
50. Wreckless: The Yakuza Missions 
51. Driver: Parallel Lines 
52. IndyCar Series 2005 
53. MX 2002 Featuring Ricky Carmichael 
54. FlatOut 
55. Sega GT Online 
56. Freestyle MetalX 
57. Spy Hunter 
58. R: Racing Evolution 
59. IndyCar Series 
60. V-Rally 3 
61. Crash Tag Team Racing 
62. Crazy Taxi 3: High Roller 
63. Freaky Flyers 
64. Street Racing Syndicate 
65. Powerdrome 
66. RoadKill 
67. Chase: Hollywood Stunt Driver 
68. Richard Burns Rally 
69. Crash Nitro Kart 
70. Mad Dash Racing 
71. Dakar 2 
72. XGRA: Extreme-G Racing Association 
73. Cel Damage 
74. Carve 
75. Test Drive 
76. Big Mutha Truckers 
77. Crash 'N' Burn 
78. Speed Kings 
79. Ford Racing 2 
80. World Racing 
81. Circus Maximus 
82. Total Immersion Racing 
83. Starsky & Hutch 
84. Test Drive Off-Road Wide Open 
85. Ford Mustang: The Legend Lives 
86. Totaled! 
87. Spy Hunter 2 
88. 4x4 EVO 2 
89. The Simpsons Road Rage 
90. L.A. Rush 
91. DRIV3R 
92. Ford Racing 3 
93. Hot Wheels Stunt Track Challenge 
94. Furious Karting 
95. Sonic Riders 
96. Auto Modellista 
97. The Italian Job 
98. Motor Trend: Lotus Challenge 
99. Jacked 
100. Group S Challenge
Making a dedicated XBOX racing cabinet just seems to be a great option.  So that's the direction I went.  I am almost finished, but I wanted to bring you up to date on what all I have done.  This is absolutely going to be my favorite cabinet, and hopefully it will be 100% tomorrow night.
Here she is when I brought her home a few weeks ago: