The DA70 arrived today, prompting this size comparison -
From left to right: Lumix 14-42.ii, Vivitar 24/2.8, Sigma 60/2.8 DN Art, Pentax DA70.2.4 Limited with hood, and Pentax DA40/2.8 Limited plus µ43 adapter with aperture control plus its mini recessed hood! Yes the DA40 is that small, and the 70mm barely larger without the hood. I just missed a bid on the DA21, another tiny prime.. another time, perhaps.
Update - While looking at DA21 prices on the GAS (Global Auction Site) I encountered a K-mount Sigma 10-20mm hyperwide for substantially less than any DA21 copies - and a very useful range with either kit. Definitely a bit bulky though. The DA21 would be relatively slow but the Vivitar fits better into the gap now. The oddball now is the 18-55, so it can be swapped somewhere for a DA50-200wr to cover above the 70mm. Looks like it's time to re-evaluate bodies .. again.