Prusa i3 multi extruder

Hi! Now I am building my first 3d printer - Prusa i3 Rework. This one will be standard. But I am thinking already about my next printer. I want to make the same Prusa i3 rowork frame, but with 4 extruders. I am thinking to put 4 bowden extruders on frame. Make two X carriages (one on each side of smooth rods) and attach two J-head hotends on each side. When I will have my first Prusa i3 ready, I will check, if I need to make the frame wider and Y frame longer, to be able to use whole table with all 4 hotends.

Since I am new in 3d printing, I would like to hear your opinion:
1. Is there some real gain in 4 extruder printer, in comparing to 1 or 2 extruder ones?
2. Could be there any problems with configuration - extruders on frame, hotends on X carriage?
3. What is your opinion about this idea in general?

Regards,
Martins

As a newbie myself, I would think the number one issue would be how to control 4 extruders.
Everyone seems to be using the RAMPS 1.4 board which only has the option for two extruders - not four. Not to mention rewriting/modifying the Marlin software. I also dont't know if any of the sloicer programs out there can accomodate 4 different colors.

Again, I'm just a newbie myself. I'm sure someone with a lot more knowledge on the subject could anser these questions.

Hi! Thanks, psneddon! There is a Duet board with Duex4 expansion, what allows up to 5 extruders. (Electronics, Duet) This would solve the extruder control issue.