If you decide to build your own panel then you're almost certain to spend far more than you would on a new X-Arcade or Hotrod.
No doubt There are people here who will claim to have built a panel for less (insert improbable figure here) but they're probably not factoring in all the hidden costs of this hobby:
* shipping costs and customs charges(many key items are only obtainable by mail order, and sometimes only from abroad)
* power tools (unless you're lucky enough to already own them)
* cost of frequent visits to local DIY store
* cost of the little items such as nuts and bolts, wire, solder etc which always seem to add up to more than you anticipated.
* Cost of wasted material due to the inevitable mistakes
* cost of buying unnecessary items to make up minimum orders
There are probably a few other things that I haven't thought of. I don't want to put you off what is a very rewarding hobby. However, the reason most people here build their own control panels is not to save money but for the satisfaction of building something unique that can actually be better than the ready made solutions out there.
There are also economies of scale with this hobby. The more panels you build the cheaper it gets because you make less mistakes and you only need to buy the power tools once.
If it's a choice between the X-Arcade and the Hotrod then I'd definitely go for the Hotrod at its new ridiculously low price. It may not have a programmable encoder however it is made of thicker better quality wood that the X-Arcade, is fitted with better quality Happ/Industrias Lorenzo joysticks and buttons, and looks far nicer than the X-Arcade (IMHO).