Too bad you don't live near me Kryten - I'd buy it off of you "cheap"
I've resiliconed many tanks over the years with good successs, though I've never had the need, or desire, to take the internal silicone out as Buk_A_neer and Rikko suggest. Once you mess with those seams it is a crap shoot and there's no reason to assume that they have weakened. Tank leaks occur when there is a failure with the water contacted beads. This occurs because they are continously exposed to water and over time they weather and weaken. The bond between the panes is not exposed to air or water and lasts a very long time (unless stressed by moving or flexing as Rikko suggests). I don't think telling people to completely strip their tanks when they need resiliconing is really practical (IMHO)
Oddly enough, I am actually redoing a drilled 130G. right now that I've picked up for $50.
It is true that having someone else do it for you will probably cost as much as a new tank though. The labour is fiddly if you want to ensure a good seal by removing all the silicone but it really isn't that difficult. I guess I like to tinker (or may be I'm a little too scottish
)
Here's a link where I describe the process
http://www.aquahobby.com/board/viewtopic.php?t=35335
Oh well, If you're ever passing through with that 130, you can always give me a call
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vapourizers