After further investigation, I think I've arrived much closer to the answer I was looking for:
Depending on the specific form factor of machines in question, there are two options:http://www.dealextreme.com/details.dx/sku.19734http://www.cooldrives.com/2sahadrtoide.html
Obviously, us Thinkpadders are gonna be looking at the 2nd option.
Judging from the pictures, modifications to the chassis may be necessary for installation of the adapter. From what I can see, it appears that the adapter itself can be semi-permanently mounted inside the HDD bay, and then the HDD caddy can be modified for 1.8" SATA drive mounting.
Over at the notebookreview forum, looks like users of the 2510p who are stuck in similar situations
as our fellow X4x users, have tested the SATA option using optical bay caddies and posted some very useful benchmarks
of their findings. Coincidentally, I'm all too familiar with the 2510p since I work with them at work almost everyday, and those 1.8" ZIF drives are painfully slow.
After reading through all this, I'm beginning to question the benefits of such a setup, and made a quick comparison of benefits and drawbacks of the 3 different SSD setup options.
With the above option:Advantages:1. Keep internal optical bay available
2. SSD reusable in future machines.Disadvantages:1. Irreversible modification to chassis may be necessary.
2. Judging by the expected lifespan of T4x notebooks, SATA SSD installed might have laughable performance compared to future SSDs by the time these notebooks really reach the end of their cycle. With native PATA SSD option:Advantages:1. Keep internal optical bay available.
2. No adapter/hardware modding necessary.Disadvantages:1. Higher cost per gigabyte (SATA SSDs currently dropping close to $2/gig while PATA SSDs are well over $2.50/gig)
2. Almost guaranteed obsolescence of the SSD.With SATA SSD in SATA Ultrabay caddy:Advantages:1. SSD reusable in future machines.
2. No adapter/hardware modding necessary.
3. Lowest projected cost
4. Availability of both 1.8" and 2.5" SSDs for installation
5. No 2010 error (not considered much of an advantage by some)Disadvantages:1. Loss of internal optical bay availability
2. (same as 2nd disadvantage of 1st option.)
All that being said, I'm starting to lean towards the SATA SSD caddy option(partially since I already have an SATA T4x caddy). Perhaps X3x user, lacking an ultrabay, would take a greater interest in the 1st option.