Ok, I am reconsidering wired ones. They seem to have some nice timer-related features.

This one here

http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=330403658644&ssPageName=STRK:MEWAX:IT

looks identica to the original Canon TC-80N3 and allows:

1. Intermittent shutter releasing (e.g. one picture per 12 secs)
2. Time exposure (e.g. 4mins 32secs)
3. Timer - delayed shutter release (up to 99h 59mins 59s)
4. Number of shutter releases for continuous shooting: 1-399 or indefinite

Costs 1/5 of the original, also.