The MSI Wind U110 suddenly stopped going into suspend more in newer kernels starting at 2.6.34. A kernel developed found where the issue is located. Actually the system did go into suspend mode, but it came right back immediately.
The issue is very easy and quickly solved, though, with a single simple command:
echo LID | sudo tee /proc/acpi/wakeup
Now I can go into suspend again, and the system still comes back from suspend as expected, nice! :)
Unfortunately for some reasons this does still not mean that suspend is working in Ubuntu 10.04 for me. Probably an issue related to the updated Xserver in 10.04. Though I can suspend and resume now, X crashes and restarts after resume.