Ordered another NOGA Big Boy from All Industrial, already a great price, but (I thought) I had a 15% "Come-Back" coupon to make it even better; unfortunately, I thought today was the 15th, which was the last day for 15%, but a call to Sales got me a 10% code, so just under $150 with tax (free shipping over $75):
I had a brain fart, and decided to see what it would be without the mag base (I plan on putting it on a clamp anyway) – cheaper to buy with the base:
And out of stock, anyway. NOGA also makes a 4" Kant-Twist™ style clamp, but it was out of stock, too:
Somewhat pricey, but a 4" kit from Doug Gray costs $65 with shipping, but MSC has one they say is "Kant-Twist" (but is a Mag-Mate in the description) for $30 on eBay with free shipping, so I'll probably give that a shot.