LTspice [0] is an excellent (and might I add free) SPICE simulator. Linear includes proper models of the majority of their chip lineup, including LED drivers. Their power supply IC models are also excellent. You can simulate a full LED driver circuit and a whole lot more with LTspice. TI also has a similar SPICE simulator [1], but it's not nearly as good, and its simulations are much slower and a bit more unreliable.
I design electronics for a living, and I use LTspice all the time for power supply and analog circuit simulations.
If by "make" you mean create the schematic in LTspice and simulate it, then I would guess about an hour or two (mostly because this might be your first time using LTspice). If Linear has a part that already meets those requirements, it should be a very straight forward affair.
I design electronics for a living, and I use LTspice all the time for power supply and analog circuit simulations.
[0]: http://www.linear.com/designtools/software/#LTspice
[1]: http://www.ti.com/tool/tina-ti