Would the laundry setting a minimum & maximum threshold in full amounts fulfill your criteria?
(e.x. minimum amount is 5 BTC at a time, maximum is 20, the only possible other amounts are 10/15)
Obviously transactions that could be pinpointed (such as a 6.8775 BTC) are not fit for laundering,
so using laundry-predefined full amounts would definitely obfuscate the origin & identity of the receiver if there is large enough volume on the site.
Yeah I've played around with different ideas for different amounts to make it more universal. What I've come up with is the idea of having your balance at the ASR to customizable to higher amounts. So for example you could set your balance at the ASR to 25 BTC. Then if you want to make a 19 BTC transaction, the ASR immediately sends the 19 BTC. Then over the course of a certain time like and hour or whatever, your client would automatically send 5 BTC transactions to the ASR to refill the balance.
If done this way then you could have transaction sizes of 5 BTC and maybe 50 BTC for people that do large transactions amounts. It's really determined by the volume of traffic. If only a few people are passing blocks of 50 BTC at a time, then there really isn't any anonymity for them.