Something that may be also worth investigating is the possibility of maintaining two connections at the same time (WLAN *and* GPRS) so that every e-mail-related connection (POP3, IMAP, SMTP) will be routed through gprs0 and every other connection (e.g. HTTP/S) will be routed via the WLAN.

This was possible with Symbian (and I loved it for it). This is obviously possible with Linux, and thus with the N900. Problem is how to set up the routing properly without interference with the standard connection tool (ICD/libconic, etc.).