I cannot confirm for sure but there was talk of a way to use the new auxilliary power blocks to make substantially larger cloakers possible. I have not tested this so do your homework and see for yourself.
Power Auxiliaries are definitely able to produce larger cloaking ships than we've seen before. Docked reactors were also able to, but the unreliability was always an issue. The most efficient possible Power Auxiliary grouping (in terms of power/block)
should be 9,891 blocks, but we also don't know the extent to which SM rounds its calculations, so anywhere close to there is pretty good, too.
At 9,891 blocks per auxiliary, you're getting 1,908,326 e/sec, 1,483,650 e/sec of which goes back into stealthing the aux group in question (1,500*989.1). That leaves 424,676 e/sec profit for each efficient auxiliary group placed, enough to support 283.1 units of mass. That's a "profit" of 28.6% of the mass you invest in power generation, as an increase in maximum supported mass (although upkeep costs for shields, thrust, etc. will cut into this a bit).
Power auxiliaries are actually a bit of a godsend for large-scale cloaking: they work best in configurations where damage to an individual part of them is limited, and fortunately, cloakers provide a perfect opportunity for such layouts! The exceedingly large dimensions engendered by the placement of an efficient Power Reactor setup also allow for Power Auxiliaries to be placed over significant surface areas, ideally in 1-block layers such that an explosion deals significantly less damage to a grouping than it otherwise could. Obviously, such a ship is still stunningly fragile, but Power Auxiliaries provide a way to give it some form, without sacrificing function.