Yes I too like lens flare hiders and incorporate them into builds, usually made from black cardstock, also I like your concept.
Here's one that I enclosed in an aluminum box and shrouded with a tube, it's not pretty but it blocks most of that lens flare, it's a nubm35 that only uses the center 8 for a neat little footprint.
I did make a beam expander for one of my nubm35 and it works for short range, but like you say size is a factor.
I have a collection of beam expanders and just scored this Thorlabs 10X at auction.
The problem with these arrays is the aggressive divergence of each emitters fast axis, but the
nubb13 with it's 4 diode arrays could at least be knife edged putting all the 4 beam clusters of several arrays onto the footprint of just 1 albeit at only a short useful distance of a few meters.
The right thing to do would be to correct each beams output with cylindrical lenses and then knife edge several rows and columns of beams to make a well aligned array that could be condensed via. telescopic reduction or for far field use focused with a beam expander.
You could use the Sharp 405nm laser diode good for close to 2W each and skip the c-lens correction as the divergence is pretty good for a multi mode laser diode, simply build your own array by knife edging rows and columns all aligned to a far field point.
A 4 x 8 would be good for for 64W - losses but the beam bundle would be much better over distance and more tightly packed.
Anyway the
nubb13 will have beams with footprint like this IIII 4 vertical bars that become 4 long horizontal bars, so knife edging the outputs from several to converge at a max working distance will be an improvement.