I installed bubble door windows on my '76 150M. The percieved "roominess" is greater, because your forehead won't hit the window when you look out, and if you're tall like me, you can put your arm in the bubble like you're driving a pickup.
In reality, though, if you're going to carry that kind of gear, in addition to the occasional passenger, a 172 might be a better choice. You can find pretty nice older 172's in the $25K range, and the fuel burn isn't that much greater.
