So my guild likes to run a fixed price DKP. The person with the highest DKP gets that item for x DKP.

I was thinking to get everyone in raid that wants an item when it drops to do /w me !bid x where x is the value of the item announced in chat, and then i check the DKP tables and when i give the item to y i write for how much DKP it got, but this seems a bit pointless since the bidding system is of no use to me. Is there any other option in game that would facilitate this kind of system?

You could just use /rolls, with the clause that your roll only indicates interest in the item and the person with the highest DKP (not highest /roll) gets it. You could also use the /roll as a tie-breaker if two people have the same amount of DKP. That's how 3/4 raid groups I've been with do it.