Your like "missing a part". This **broken link removed** is probably for car audio, but it does have the controls your after. Note, no mention of power requirements.
Generally this falls under "active crossover".
So, after receiving the feedback from everyone thus far, I have decided to take your suggestion.
I just ordered the SSL SX310 as well as Clarion's MCD360 from Amazon. That way I can play with two units for comparison. I'm hoping that by using one of these active crossovers I will be able to avoid what Audioguru mentioned with regards phase shifting and "notching". It also helps simplify the sub woofer control.
My question with regards this approach (using the MCD360 as example) would be:
Will I still be able to utilize a 10k stereo log pot between the head unit and the active crossover for gain control? Or would I need to match the input impedance that the MCD360 is rated for?
Here are the specs for the MCD360:
Power Source: 14.4 volts DC negative ground
Input current: 0.5 amp max
Disortion: 0.01% THD at 1V output level
Frequency Response: 10Hz - 30kHz - 3dB
S/N Ratio: >100dB
Separation: 60dB
Crossover Slope Rate: 18dB per octave 3rd order butterworth
Input Impedance: 20K Ohms
Output Impedance: 100 Ohms
Output Gain: 1:2(+6db)
Output Voltage level: 5 volts max
Dimensions: 152mm x 180mm x 43mm