This is a really good idea, and probably not difficult to implement.
As far as ABS+HIPS is concerned, I must say that I have not been impressed with using HIPS as soluble support material for ABS. The D-limonene used to dissolve the HIPS doesn't work that well and can damage the ABS, and even dissolve some brands of ABS. Some brands of HIPS also don't dissolve well in D-limonene. I've found this process to be less than ideal. D-limonene is a very strong solvent, and quite expensive. It can dissolve a lot of things, so you need to handle it carefully.
I recommend giving other alternatives a try.
If you need truly soluble support, probably the best one is PVA rather than HIPS. PLA+PVA works well. If you look at reviews for PVA on Amazon you'll see a lot of people are happy with it as soluble support. PVA dissolves quickly and completely in water after only a few hours, even for large prints. For large prints, HIPS can sometimes take days to completely dissolve in D-limonene. At that point the ABS is damaged also. With PVA you can't use ABS though, you must use PLA. PVA is more difficult to print that HIPS, but it's much easier to remove from your prints than HIPS is. Water is super cheap compared to D-limonene, so despite PVA costing more than HIPS, you save money by using water instead of D-limonene. The main problem with PVA is that it can clog your printer if you print it at temperatures above 200 C. Also, when using PVA, you should always remove it from your print head after use (run some other filament at 195 C to get it out of your printer's head).
If we could specify a different material for the dense support layer only, then you could print PLA with PLA support, but use PVA as the dense support in between the object and it's support. This would be great. PLA is practically warp free, and can create very accurate support material. PVA is expensive and doesn't print as well as PLA does. If PVA is used just for the dense support layer, then it wouldn't matter all that much that it doesn't print as accurately, and this would also greatly reduce costs.
If you just need support that's easy to remove, and don't need soluble support then another combination I like is printing PETG on PLA support. PETG has properties similar to ABS. It's got good temperature resistance and is slightly flexible like ABS. PETG and PLA are practically warp free, unlike ABS and HIPS, and neither require a heated build plate. So your prints come out with much greater accuracy. PETG prints very well on PLA and visa versa. After the print is done, the PLA and PETG easily snap apart from each other. I have used this combination many times and am very happy with it. While you can do this also with ABS+HIPS, the result is not as good because ABS and HIPS both warp considerably, and seem to be more difficult to separate from each other.