You might check here:
http://www.proamauto.com/
That's where I got a set for my '73 . Part numbers: B46-1173front and B46-1587rear.
They don't list a '72 model P-30 but they have a toll free number: 800-847-5712

There is a vendor in Quartzsite selling Bilsteins for the front of P30s and P32s for $25 each. Says they were take offs from Winnebago Vectras or something. Says they put on Monroe coilovers to handle the extra weight.

Anyone interested, I can get more info, as Susan needs her Q fix every day now.