Ok, just for completeness: Not all TLA7012 are fitted with the same main board. I don't know the manufacturer of these industrial boards, but that doesn't really matter, because replacing a whole main board would be a bit much for an upgrade.
The main board in my frame is based upon the Intel 915GM chip set and the fasted CPU compatible with it, is the Pentium M780. The CPU currently fitted is a Pentium M760 and the only difference between the two is that the M780 runs at 2.26GHz, while the M760 runs at 2.0GHz. This measly 13% extra CPU power will not make the look & feel any smoother.
The main board itself is fitted with two SO-DIMMs of 512MiB each, 533MHz, CL4. The chip set is said to be compatible with DDR3, though DDR3 SO-DIMMs are noticed differently due to electric incompatibility. So the only upgrade possible here is to increase the size, but not by much, because the 32-bit physical address only offers 4GiB of address space. With PCI usually taking 1GiB, there's only 3GiB of address space left for RAM. 2 GiB DDR2 SO-DIMMs do exist, but rare, hence expensive and unlikely to be compatible. Corsair 1GiB SO-DIMMs cost €12 per piece, so that's a no-brainer.
An Intel DC S4600 240GiB SSD costs around €180 and is enterprise-grade, hence reliable and power-fail robust. This will probably do the most for the look and feel.
Now let's see if we can upgrade this beautiful beast! It doesn't seem to like all the Windows XP updates...