Gold or DKP?

Something which is currently debated on our guild forum: Offspec items.
We use a DKP bid system for items and we have a rule that people can buy an offspec item for half price, that is if no one wants it for the correct spec.
So if a huge weapon drops and a tank wants it and no dps wants it, they can have it for half price.

Still many stuff gets sharded.. people rather not spend their dkp on offspec items, items they rarely use while in the raid or even outside of that.
Stuff which still could benefit our raid at times, imagen that enhancement shammy is required to spot heal on the next boss as people with mana can't get into melee range of the boss... would be helpfull if he had some healing kit then.

One of the ideas thats around at the moment is paying good old fashion gold for such an item which is about to get sharded, but only if it is an offspec item ofcourse. The price would be something relative to DKP, 2 times the cost of DKP in gold for example... which scales pretty well with the variation of item and is never debateable.
Now i would prefer that this money is shared among the people in the raid at that point but we need a simple way to handle it. We don't want 24 people to trade the buyer for their share of their gold, that would delay the raid way too much. It also might goof things up as quickly overview is lost who got their gold and who didn't.

Now a while back i read an article about a guild that bids on items with gold instead of dkp, the example was a guy buying the Al'ar mount for a sick ammount of gold. This proofs to me that there are methods invented for this already, people already have a way to handle this.
Do they have an addon which registers who is in the raid and sort things afterwards? Or once a month even?
I can imagen there are easier ways to keep track of things then making screenshots, writing down the date (so you can find the correct screenshot) and gold ammount + the buyer.

Any ideas?