I recently decided to upgrade my Fujitsu U810 with a solid state drive.
Unfortunately, since the U810 only offers a PATA interface the options are quite limited to just a few high-priced (compared to SATA) 1.8″ SSD models by either Samsung, Sandisk (SanDisk SSD UATA 5000, discontinued) or MTRON (MSD-PATA3018-032-ZIF2 et al.).
I went for a 64 GB SLC drive manufactured by Samsung. The exact model name is MCCOE64GEMPP. The same 1.8″ PATA-drive is available as bulk version without the metal enclosure that is protecting the PCB: MCCOE64GQMPQ

Here are some photos of the drive itself and how to install it in the U810. Note, the drive is 5 mm high and will fit into the U810 without any modifications.
Also keep in mind that the U1010 has a different connector (50-pin IDE instead of ZIF), so these ZIF-drives will not work here. However, there are reports on UMPC Portal that suggest that it is possible to get a replacement connector flat band cable for the U810 that is the 50pin IDE cable, so I guess it is also possible the other way around for the U1010.

Here are the obligatory benchmarks comparing the new SSD against the old Toshiba MK1011GAH 100 GB hard drive that was previously installed in the U810:

Needless to say that applications cold-launch a lot faster with the SSD. (Firefox with 12 add-ons: ~10 s before -> ~6 s after, Chrome: ~3 s before, ~1 s after, Thunderbird: ~8 s before -> ~3 s after).

Startup time was reduced quite a bit but not dramatically. However, returning from sleep and hibernate saw a huge improvement. Unfortunately I can not provide values of the old drive, so no comparison.
I did not notice longer battery run times. However, the whole system runs a lot cooler because the SSD naturally does not produce heat as extensive as the HDD did.

I am satisfied with this upgrade – especially since it has boosted compile-times when working with CodeGear RAD Studio and Delphi – due to the great performance when accessing, reading and writing small files. Your mileage may vary.