You can upgrade to a VPI Classic 2 or VPI Classic 3 arm (I did) but it will involve some minor drilling (note: the VPI Classic 3 tonearm provides on-the-fly VTA adjustment).
As for other "non-VPI' arms, you will have to drill through the plinth for the tonearm wiring unless you get something like a Tri-Planar VII Ultimate tonearm ($5,700 US).
The thing to remember with some of the VPI turntables, like the Scoutmaster, is that the "acrylic-like" material that VPI uses, gets sticky when it heats up. It sticks onto the drill bit, making it easy to mess up.