
James,
Since no one else has jumped in here I'll give you my opinion for whatever it's worth. If I were in your shoes I would get these speakers
Behringer B2092A Active Subwoofer (360 Watts) - $230
Behringer Truth B2031A High-Resolution Active Studio Monitors 225 Watts, 8.75 Inch Woofer - $340 /pair
This setup is affordable and will adequately handle 16' pedal ranks.
In the future you could use these with additional pairs of the B2031A monitors for a multi-channel setup.
I must tell you, having run Hauptwerk in stereo 2.1 myself for a while while testing and configuring my PC hardware, there is a HUGE difference in realism between a stereo setup and a multi-channel (say 8 channels) setup.
Best Regards,