Linear Tech's AD8009 highspec VIdeo amp is your friend here - costs about 5 Benjamins each from Chicom dealers . THese have been successfully used as driversfor RD 15HH Mosfets in class A to get 7 W linear out. Will give up to 24.7 dBM LINEAR power into a 50R single ended load at 12 V supply, without sweating the silicon. that's 7.7 dBm over your start position.
For Filters, I'd consider just a Heist Two of Hans the genius's Qmx + two band filters to make up a four Pi topology set that would cover from 40-30-20-15 Mhz that does not need to be switched . It would be 50Z in 50 out ... anything outside there in frequency - why bother :-)) ??
Obviously 80 and 60m bands are implicitly covered in any case . Nothing new under the sun - if QrpLabs in Istambul have not done it , then the crows working for the CIA or NSA probably have.
Timothy Fidler