There's this program called HTTP Tunnel, to be found
www.http-tunnel.com, (stangely!). It's got a feature that it can map ports for programs that don't support SOCKS (therefore LimeWire). LimeWire uses port 6346, which can be mapped to a local port (1024 upwards on mine) thoufg HTTP Tunnel. Then you get limewire to connect to that port on the localhost (e.g. 127.0.0.1:1024). You need to map up probably at least the router.limewire.com and connect1.gnutalla.com in HTTP Tunnel.
Having done all this..... it doesn't work. But it should, at least I think. I sort of connects sporadically, stays connected for a while, then drops off. But I think if someone spends long enough trying to get it to work (not me) then it might.
Could be useful for universities which often only have an HTTP proxy (because that's all they need of course......).
If someones else manages to get it working, post it up here.