Special Link Questions

I like how with pretty urls, I can go to /wordpress/tag/red

Is there a way I could go to a page that would list items with more than one tag? ex: /wordpress/tag/red,yellow,blue

I like how I can go to /wordpress/topic/flowers

Is there a way I could link to a page that would list items with tags that fall within a category? ex: /wordpress/topic/flowers/tag/red

Ultimate ex: /wordpress/topic/flowers/tag/red,yellow,blue

Thanks for any help with this issue and any plug-ins you might be able to point me towards getting this job done.