Thoralf take a look at this proposal: Old (and dust) tx merkle tree bitmasked snapshot compression
As this also does what you are looking for and can work without owning any iota upfront or requires it to keep it locked.
That solution would solve multiple problems and we can get rid of timewarping entirely and the main long connecting proof will be part of each node. You only need the tx path to(/from) a dust transaction as proof. The rest is done by the nodes.