In 2008, a 403(b) plan was terminated and all participants received a distribution. Can a former participant who now has a paid up annuity roll that to a 401(k)? In other words, is their paid up annuity still considered a 403(b) and eligible for rollover?

Isn't that the purpose of reg 1.403b-10(a) which allows a distibution of a 403b contract to be rolled over to another plan under 403(b)(8). Since the contract remains subject to all of the rules under 403b after distibution from the plan (e.g., MRDs) it is eligible to be rolled over to an eligible retirement plan.