Good suggestions on mic amps.
Roadworthy, I got your pm about which mic pre to use for your dreadnought guitars. It does sound like you need to upgrade to a good quality pre. The other suggestions are all excellent. I've been using mainly neve, telefunken or chandler pres because those are the nicest outboard pres I have easy access to. I've heard great results from the hardy and from manley on collings guitars too.
If I were you, I would search for info about pendulum, john hardy, and brent averill pres among many others.
I think, though, the most important things about recording acoustic guitars well are microphones and placement and room.
"Let's be discrete"