I'm looking for higher seat with round front. 1-piece is nicer.

Doesn't have to be ADA height, but wondering what is out there. I love my Toto Ultramaxes, but this stool will be for my 80 y.o. parents, and I was wondering if there is anything out there I should look at?

My suggestion would be to examine the Toto Drake ADA. (CST 744 SL ADA) You do have to realize that ADA toilets do not come with round bowls, and this is a 2 piece, but unless there are overpowering reasons to go with a one piece round bowl, this would be an excellent choice. You can see these by clicking on "Toilet Reviews" at the top of this page, then click "Shopping" and finally "Toto". This will give you a rundown on all of the Toto models. Terry's prices are perhaps a tad less than you may have to pay, but they are seldom sold at MSRP. Another good choice would be the Toto Altramax ADA. It is a one piece, also elongated bowl only.

ADA, (American Disability's Act) requires a finished seat height of 17" -19"

604.4 Seats. The seat height of a water closet above the finish floor shall be 17 inches (430 mm) minimum and 19 inches (485 mm) maximum measured to the top of the seat. Seats shall not be sprung to return to a lifted position.

It doesn't say anything about being elongated here, but most tall bowls are elongated.
One of the few two-piece round and high bowls was the CST733F Toto Dalton, which is no longer being made.
Toto doesn't make a one piece high round bowl. They do have standard height round bowls.

http://www.ada.gov/regs2010/2010ADAStandards/2010ADAstandards.htm#c6

For older people, unless a door swing is hitting the bowl, the elongated is much better.