Honestly, your best bet is to get rid of X60T and just buy a X61T with SXGA+. You might end up doing better from the financial standpoint in the end.
I buy and fix these computers as a hobby, and any practical usage I manage to get out of them is pure bonus. Therefore, I don't plan to spend much money on them. For example, this X60 tablet only cost me $40. Buying an SXGA+ X61T for ~$400 defeats the purpose, unless I can get a broken one for much less than that and then fix it.
My tentative budget for this potential upgrade is $200. If the cost of getting an SXGA+ panel is much higher than that, I will simply not do it.
I do, however, wish to hear some suggestions about the "getting rid of" part. If I decide to sell either my X60T or X41T, where am I likely to get a fair price?
I got my replacement screen from this ebay seller: http://www.ebay.com/itm/IBM-LENOVO-X60- ... 20be53c5bd
Not cheap, but I really didn't care. No problems other than what's to be expected from putting an X60t screen into and X61t. (Digitizer cable not matching up.)
Indeed, the seller you listed has the exact part number and all, and it's the most straightforward swap possible. But as I said, I'm more looking at it as a hobby, and the $300 price tag is honestly not worth it for me.