Combing Hard Drives

Hi, I've got a 300 gb Elements external hard drive and an 80 gb Beyond Micro external hard drive. I had the idea to combine both the drives into one enclosure. This is just a concept... is it doable? Is it possible to add the 80 gbs to the 300 gbs device so in total I'd have 380 gbs, or can I have two drives in one existing hard drive enclosure? Can I do this at home or should I seek professional guidance?

Yes, it's very much possible, you just need to find an enclosure that features JBOD, which unlike RAID, allows you to combine different sized drives.