The LCTHC and G540 make a good low cost setup and you can get an optional G540 Interface Card that makes the interconnect a single UTP cable.
I would like to point out some things for your consideration.
The LCTHC lacks a lot of the advanced features that our MP3000-DTHCII offers. Here is a Features and Comparison Chart to show the LCTHC VS the MP3000-DTHCII. Note that the MP3000-DTHCII is more than just a Digital Torch Height. It is an advanced BoB with double the inputs and outputs and handles up to 5 axis of motors. With the added inputs it still leaves you with the original ones for Homes and Limits. It is a one parallel port solution. Stock on the MP3000-DTHC are two high current relays (besides the Torch Relay ).
The LCTHC lacks the tight integration with MACH3 and does not have the digital "pickup" module like the MP3000-DTHCII and does not offer the single cable interface to the Hypertherm 45/65/85. Here is a link to an interactive screen that shows part of the custom DTHCII screen and what all of the controls do.
You can plug a G540 into the MP3000-DTHCII (single 25 pin cable) and have all of the features of the higher end product. While the total cost is somewhat higher you don't have to buy any other hardware.
The MP3000-DTHCII is used in all our plug-n-run systems and is the only product that supports the new Hypertherm RS485 Serial Interface.
We do not offer the LCTHC to OEM (table manufacturers). The difference in cost is so insignificant on a table that shorting a customer on features makes no sense.
There is a lot more to plasma cutting than running a torch up an incline. The response time of the THC is a function of the Z speed and motor. Our electronics are WAY faster than most motors can move. Even averaged you can get several hundreds of moves per second. It's all the other "stuff" you have to do in plasma cutting that makes it either a pleasant and profitable experience or a real PITA.