Try a North Face Mountain Jacket.
You will pay through the nose (mine was $320 about 4 yrs ago), but you will have something that you can use to stay dry in the shower (literally), and that will last you forever. My North Face jacket may well be my single favorite possession. This is an outer shell, which can be combined with an inner layer from North Face or any other merchant.
Message edited to add link:
http://www.thenorthface.com/code/pro..._standard.html
Best way to get a good price is to call up ski shops and try to negotiate -- shouldn't be that difficult in the summer. They may not be allowed to advertise lower prices, but they can usually be talked down.
[This message has been edited by pynchonesque (edited 06-07-2001).]