I have an idea for a dip tube in my MLT that goes to a tee and then out the keggle on opposite sides. One side would go towards the HLT where it would be connected via a three-way valve to the HLT and the pump-RIMS tube. The other side would go out to the BK. See the schematic below. The idea would be to use the three way valve to send water from HLT to the pump for doughing in and for sparging and from MLT to RIMS for mashing. The wort would exit to the BK during the sparge. I'm planning to use tri-clover connections, so I don't think it will be too difficult to slide the T shaped dip tube into place, but there won't be much play on either side. It'll have to be pretty tight.