I have just performed this upgrade myself (T60 + IDTech IAQX10N), and thought I'd share some of the pitfalls and observations that I haven't seen mentioned anywhere else.
1) If your EDID isn't suitable, you are likely to find that POST and low-res screens only show vertical stripes. That's what mine did. But despite this, you may find that once Windows boots, it actually queries the EDID, gets the 2048x1536 mode information, and works fine.
2) The EDID data floating around for this screen is not entirely sound. I have found that it works OK for POST and Windows, but some other operating systems including some versions of Linux (specifically, RHEL6b, but there may be others) seem to make different assumptions (possibly rounding of timing information to a pixel multiple greater than 1) and fail to work properly (once the high-res text mode kicks in everything will crash with a blank screen).
Eventually I pinned it down to either vsync timings or sync polarity. Either way, the EDID that works for me for POST, BIOS, Windows and all Linux distros I have tried is here:
EDID BYTES:
0x 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
------------------------------------------------
00 | 00 FF FF FF FF FF FF 00 30 AE 49 40 00 00 00 00
10 | 00 13 01 03 80 1E 17 78 EA CD 71 91 55 4F 8B 26
20 | 21 54 56 21 08 00 81 80 A9 40 01 01 01 01 01 01
30 | 01 01 01 01 01 01 29 40 00 60 80 00 10 60 10 10
40 | 88 00 30 E4 10 00 00 1E 00 00 00 FD 00 30 32 4C
50 | 4D 11 00 0A 20 20 20 20 20 20 00 00 00 FE 00 49
60 | 44 54 65 63 68 0A 20 20 20 20 20 20 00 00 00 FE
70 | 00 49 41 51 58 31 30 4E 20 51 58 47 41 0A 00 D9
If anyone is contemplating doing this, I highly recommend it.

If your eyes can handle the pixel density, it is absolutely awesome. I use this thing for work all day every day, and my productivity has increased considerably with the extra xterms I can have on the screen at the same time.
Word of warning, though - BEWARE of suppliers claiming to have these IDTech panels available for about $120 (if you Google around for a best deal, you'll no doubt find who I'm talking about) - they will just take your money, and you'll have to chase disputes via PayPal when they never ship the part and don't respond to refund requests. Save yourself the trouble, pay double that amount (what the screens cost anywhere else) and just be done with it. I got one from a Chinese supplier on Alibaba, for example.
I hope this is useful to someone.