Yep, rings glued right to the suit. Not too complicated of a process but it's probably not something a DIYer would want to do as a first project.
I'm not that familiar with DUI's suits, just guessing that the sleeves would be about the same diameter because most latex cuffs tend to be within the same size range.
Viking's suits are easily adapted to permanent rings so I don't see any reason your suit couldn't. Having cuffs attached to the rings in addition to the glove is also pretty common with Viking's suits. I don't know how practical adding cuffs to a DC ring system is, so you should probably get in contact with a good drysuit repair joint that handles a wide variety of mfgrs, like the guys in MN.
http://drysuitrepair.com/
If for some reason your DC rings won't fit the bill, the new bayonet latching ring kits from Viking (made by Si Tech) are something you should take a look at.
Replacing cuffs on a drysuit is a whole lot easier than you may think. Here's a drysuit DIY cuff replacement slideshow you can take a look at:
http://comdive.com/cuffs.zip
It's a zipped file of about 750kb in size. You can do a right click & "save as" or whatever.
If you slap some good heavy duty cuffs on your suit you should be able to go years w/o needing to replace them, as long as they're properly maintained.
