Why are m-of-n transactions not used today? BIP 11 supports m-of-n transactions. While BIP 16 and BIP 17 are being debated and voted upon, I have to ask: why haven't there been evidence of BIP 11 used in for m-of-n transactions?

All that BIP 16 and BIP 17 do is shift the cost to the recipient. This is healthy for the long term cost structure, but it doesn't mean that BIP 11 style m-of-n transactions aren't usable today, does it?

Have it been used somewhere and I just don't know about it? Or is the current protocol not usable for m-of-n transactions?

See also this question about BIP 12, 16 and 17.
There are some m-of-n transactions in the blockchain (blockchain.info - block explorer) but they have only been recently added to the standard transaction types.

However the reason why they are probably not in wide spread use yet is there is no gui based client that can construct one. My Wallet will be able to construct them soon, I don't know how much demand there will be for usage.

The way I see it BIP 16//17 and m-of-n have different use cases. The drawback of P2SH is that you need to share the script with the recipient in order for them to know they have received a payment - you also need to store the script. While this might be ideal for split key wallets, (where the wallet owner already has the script) it is awkward for use with escrow transactions. If you receive an M-Of-N escrow payment notifications can work out of the box and you can use existing vanity addresses.