If someone is interested in your player they will prolly send you a BB-mail.
Is posting player skills in forum forbidden? To my knowledge you can not link players that are transfer listed. You can post your whole teams skills if you want to as long as they are not transfer listed.
You could write: I'm interested in selling my player [player=blablabla] waiting for offers via BB-mail. Or you could just list your player for a reasonable price (or a bit below it if you are unsure of his value).
There is no need to spam anyone. I'm going to say it once more, if the price is right -> player will always be sold.
Who wants to read forums to find suitable player, if he can filter players on TL?
Why to add new taxes just because you are lazy to set Maximum Current Bid? It allows you not to see players you don't want to see.
You can think of some administration fee which wouldn't depend on asking price but would be the same for placing any player on TL.
Maybe you can think of some other impact of placing player on TL such as game shape drop (because player is stressed by possibility of changing team - but sometime player can look forward to transfer ...). It could be acceptable for me.