Garth--
If you don't mind using old ACS 2012-16 data, then try the CTPP database. data5.ctpp.transportation.org/.../
It has at least four crosstabs that include household size (5 levels) X household income (number of levels varies)
Possibly the crosstabs you want are
A112208 (not available for all geographies)
or
A112301 or A112303 or A112306 (each of these has a third variable cross tabbed)
CTPP is updated roughly twice per decade. I'm not an insider -- but the last I heard was that CTPP from 2017-21 survey data would be published in summer 2024 (and that's optimistically = if disclosure review board is happy and there are no other bureaucratic snags).
hope that helps.
--Todd Graham