Wow...that's a lot to take in.
First, I think going for a SSD is a great idea...but, are you going to fit an OS and your applications on a 32 gig drive? Seems like you're "laptop bound" so I won't suggest a new i7 desktop with WD Raptor drives; doesn't get much faster than that.
Next, backup. I dunno about the external hot swappable RAID; what I think you really need (and it may be costly) is a good tape backup unit. Not the old TARVAN drives we used to have, but a real up-to-date tape system. Go to any modern data center at a company and I promise you their networking group is running nightly backups to tape; perhaps even 2 copies (on on-site and the other off-site). And they probably have a 10 tape backup system running incremental backups on a 2-week cycle for any given system.
I dunno how much money you have to spend, but it sounds like you possibly need an laptop upgrade with some type of file server as a backup medium (hard drive, tape, burn to blu ray etc.)