Well, it appears that "free" leaders can apply as well. Also if a country reaches higher levels, then drops down to 1 or 2, it may allow a proposal as well.
Supposedly The Empire of Ryan is "free" status and says it reached maximum level of 3 already, but is currently at 1, and is being voted on now by the General Assembly, 39 for and 38 against so far :S. That country is a good candidate, but it seems to question the "rules" that were generally understood. Regardless, it seems deserving.
Maybe an agreement could be made to give "free" leaders a lesser amount in the future to make it more fair, then allow the full 5T SC$ for "full" leaders...but, good luck figuring out which is which.