Also - You can't "build and execute" at the same time. EXEC wants a static string (meaning - something fully built before you pass it to execute), not some concatenation operation happening inside the EXEC statement.
AHA! This is the part I did not know, but figured out thru trial and error. My SQL was good, it just wasn't going to work by constructing it within the param list for the 'exec'.
The funny thing is that BOL (SQL 2000) contradicts this (nothing new there)...it says you can concatenate stuff together inside the EXECUTE string...
From BOL...
EXEC('name_of_8000_char_string' + 'another_name_of_8000_char_string')
EXEC ('DROP TABLE ' + @tablename)
Perhaps there was something in my test code that it specifically did not like, such as the 'char(39)' because it absolutely would not run until I put it in a variable first, like you said Matt. I will test further and see...it isn't a big deal, but you like to know these things for future reference.
If it was easy, everybody would be doing it!;)