  We present recent high angular resolution (9") Sunyaev-Zel'dovich effect
(SZE) observations with MUSTANG, a 90-GHz bolometric receiver on the Green Bank
Telescope. MUSTANG has now imaged several massive clusters of galaxies in some
of the highest-resolution SZE imaging to date, revealing complex pressure
substructure within the hot intra-cluster gas in merging clusters. We focus on
three merging, intermediate redshift clusters here: MACS J0744.8+3927, MACS
J0717.5+3745, RX J1347.5-1145. In one of these merging clusters, MACS
J0744.8+3927, the MUSTANG observation has revealed shocked gas that was
previously undetected in X-ray observations. Our preliminary results for MACS
J0717.5+3745 demonstrate the complementarity these observations provide when
combined with X-ray observations of the thermal emission and radio observations
of the non-thermal emission. And finally, by revisiting RX J1347.5-1145, we
note an inter- esting correlation between its radio emission and the SZE data.
While observations of the thermal SZE probe the line of sight integral of
thermal electron pressure through a cluster, these redshift independent
observations hold great potential for aiding the interpretation of non-thermal
astrophysics in high-z clusters.
