According to the Moell T-hunting book the 1n4148 diodes introduce more switching noise and more potential for cross-modulation from strong signal sources.  A quick look at my friendly non-local distributor shows that there are SOD-323 PIN diodes for about $0.40 and even cheaper ones in different footprints.  So in a four antenna system I'm using eight diodes.  I'll go cheap on something else.  Off for diode shopping...  Or more PCB redesigns....