Welcome RHC. I think some people are being polite, but let me just blunder into this. I don't think very many TBN folks are eager to "recommend" a 3 pt backhoe for any tractor. Almost every discussion I've seen on backhoes has at least one recommendation to avoid the 3 pt type backhoes. That's because they generally have less digging ability, can be more difficult to put on and remove and have a potential to cause damage to the tractor or injure the operator. The 3 pt type of backhoe remains on the market because it is somewhat less costly and with proper setup can be adequate for lighter duty use. But operating that type of backhoe can still place a lot of stress and shock loading on the tractor rear end that does not occur with a subframe mounted backhoe, at least not to any similar extent.
Kubota apparently stopped offering a 3 pt backhoe when the current series of tractors was brought out about 5 or 6 years ago, going to subframe-type BH's instead. Prior to that, on the Grand L xx30 models such as yours, the Kubota 3 pt BH was a BL4690B. I don't know if a Kubota dealer could still get you a new one, but you might find a used one with some looking. There are also some good 3rd party brands, but if you're looking in that direction, why not simply specify a subframe configuration for it?