Which is the reason T-N discontinued 'em, along with any parts for 'em...there's no profit in repair parts, especially parts that are only needed about once every 10 years.

They still have rebuild kits, but won't much longer...the only hardware that's still available is what's left in inventory. Sooner later yours WILL need something that isn't available any more, and then your only choice will be to pay to have it machined or replace the toilet.

The most durable plastic toilet is the PH II...it's not likely to last 100 years, but it will last at least 20 with minimal maintenance...at least twice as long as the Groco HF and 10x as long as a Jabsco. The only US made bronze "throne" now is the Groco Model K, but they don't have anywhere near the lifespan of the W-C Skipper and Imperial...they have a very nasty tendency to start recirculating after about 20 years when the piston bore wears beyond spec and the rings allow pressure to blow by.. You can replace the bore housing but that would be more expensive than replacing the heads completely with a PH II. http://www.groco.net/SVC-MAN-07/Sec1/pdfs/K.pdf

However, if you have an extra $16,000 lying around to spend on a toilet that will last at least an entire millenium, there's still the British Blakes Victory...or for a paltry $6000, you can have the Baby Blake. Prices include VAT, btw.