Unless I'm mistaken, when you turn a level 100 skill legendary you're refunded all your perk points, meaning a level 100 character would have 99 perks to spend regardless of number of legendary skills (no perk at level 1). Since there is no level cap there is no limit to the number of perks you can get, which means infinite levels and perks...but really there's no reason to go over 251 perks, the total number of perks across all skills. This puts the soft level cap at level 252 (again, no perk at level 1).
Conclusion: Anything above level 252 is just abuse for more magicka/health/stamina...
Any objections?