Burke is very interested and now available since "The Fantasticks" didn't run another 20 years. He was going to be the resident El Gallo for the anticipated forever run and take short lengths of time off to pursue other projects but oh well. Shrek might be his Tony winning role. We'll see what happens. Norbert Leo Butz is interested as well.
Not to be contrary - but as with any role - it's not anyone until the contracts are signed, sealed and delivers AND the official announcement comes in from the press office. Until then - it's all rumors and speculation.
"A little nonsense now and then is relished by the wisest men" - Willy Wonka