So, what about this... (please excuse my extremely crude digital sketch. I didn't have access to a proper drawing tool and drew this schematically rather than to anything approaching any scale. Blocks and lines are moved out and away for clarity.
Why not put the reverse purchase downhaul vertically (or diagonally) on the luff, rather than across the deck horizontally.
In this drawing, the Jib is Yellow (just in case you couldn't recognize what that is...), The Mast, Deck and forestay are black and the Jib is shown deployed.
The Jib Halyard is in Blue as well as the halyard block up on the mast.
The Red line represents the downhaul, which is attached to the head of the Jib with along the halyard. The downhaul (red) comes down through the hanks to a turning block fixed to the deck (stemhead?), the downhaul line exits that block and through another turning block which will be movable, and from that block down to the deck where its tied off (again stemhead or equiv.) The movable block is attached to a topping lift (in my drawing I called it a downhaul halyard which I know was wrong, but couldn't remember the term topping lift) which is the green line. The green line runs up to a block above the jib halyard, and then back down to the deck.
During normal sailing, the green line is taut, keeping the red downhaul taut, and since they're on the luff, generally they should stay out of the way. The downhaul blocks are down at the tack point and should for the most part be out of the way and out of consideration.
To pull down the jib, the halyard (blue) is release, and the green line is pulled to draw up the red movable block, pulling the jib head down with less line in the cockpit.
So that's the idea anyway... Thanks - Scott