Have you attempted to clean out the port at all? I'm not sure what the best way to do this would be...I know you can get some electronic cleaning goop that sticks to crud and you can buy it at The Source in Canada, but I don't know where you're from so I couldn't tell you.
Some options that could work, but would be a hassle so I would try any other options first, would be to use the app DoubleTwist Airsync and connect your microSD via another device if you need to access those files. DoubleTwist AirSync allows you to sync photos, songs, and videos, all over the air. The catch is you have to pay for the app. You might want to try the free service of USB connection...I doubt it would work, but it would work separately from HTC Sync. I'll post the barcodes for both the base app and the AirSync app at the bottom of this post.
An annoying option to have access on your PC to your SD card would be to get an adapter and use it in a phone that allows you to view the card on your PC...that would require constantly taking your card in and out of your Legend, which is a pain.
If nothing else, it would be worth a shot to do what Adi suggested. The worst that could happen is that they laugh and you don't get your phone fixed. Its not like they're gonna make you give it to them even if they can't cover it under warranty.
DoubleTwist Player (free):
DoubleTwist AirSync (US $4.99):