It depends on what it is that you don't like about them, is it the feel of the keys or the switches?
If it's keycaps you have a lot of choice - ABS are cheaper ones and feel cheap (whether they're single mold or double-shot), or there's PBT ones which feel better to type on and are made better too.
Check overclockers, they have the entire Ducky range of keycaps - decent quality.
Problem is, keycaps are a niche, but that is also a good thing as there's a LOT of variance out there - check
http://www.ctrlalt.io,
http://pexonpcs.co.uk/,
http://www.wasdkeyboards.com/,
http://www.pimpmykeyboard.com/ and also
http://www.geekhack.org for group buys.
If you want something outside the Ducky range then as above will sort you out, but they're generally all US-based, so expect import fees! 😧 PimpMyKeyboard is a store ran by SignaturePlastics - the company which pretty much all of the groupbuys on GeekHack run (just with their own designs), so they're generally high quality keys :]
As for Rubber keys, I don't think I've seen any - and metal keys generally are not that good quality, the stems are usually too big or too small, so they either wobble or need modifying to fit properly.
Also, I'd try experiment with o-rings too, they make a lot of difference! What switches do you have currently, Reds?
