sticking up for the vet....
might be highly contraversial, and i am always open and interested in discussion on this, being a vet student, but i'd like to stick up for the vet, at least partly. I dont know you or your bun well enough to comment fully, or how well you know your vet either, but i would actually rather a vet that encourages another form of action, such as giving the bun to a knowledgeable rescue, for an owner that "appears" unable to either cope with the treatment/recovery or cost of treatment, rather than telling the owner to soldier on and flounder alone. I dont think this is a personal insult to you, he/she is simply trying to work out what is best for both you and your rabbit.
In terms of payment and insurance, definately dont commit fraud, its a very bad idea for you, unlikely to work, very unlikely to benefit your bunny and will destroy your relationship with your vet, and potentially any other vet you move to, as bad payers/creditors/dodgy insurance claims are recorded at most vets and often passed on with transfered medical notes. in this case you just have to accept that you havent had him insured so will have to incur the full cost yourself, which you appear prepared and willing to do. I think AlisonA was right that 2 dentals in a month is highly unlikely to occur again, and like someone else said, a few corrective dentals in a short space of time may cause sufficient realignment to reduce the frequency of dentals in the future and the severity of the disease. If you do need fairly regular treatment most vets can offer a reduced price as part of a treatment plan, including payment options. my college has mixed opinions on conscious/sedated dentals, as someone said they are not as effective, and have other potential repercussions, but they are a viable option if you can find a suitably rabbit savvy vet, but probably not advisable or likely to be undertaken by your average pet vet.
Someone mentioned VAT - i think thats a nice idea but i dont think it would work. some vets do charge extortionate prices and there should be better regulation on these things, and the best way to deal with it is vote with your feet. if vets loose business they often lower prices. having said that, costs and overheads can be very, very high and i know some vets i have worked for make little profit on routine work such as dental, spays, vax etc in order to encourage people to get them done and avoid future problems.
ATB for your bun, i hope his condition does improve and he becomes a hay monster!