This actually makes a lot of sense.

I have a spare set of heads that I may start experimenting with.

The only thing bothering me would be the lie angle of the set because, as you say, the long irons are more upright than the short irons.

I'll build and weight match a 6, 7 and 8 iron using shafts of the same length and take them to my practice area then report back on my distance differentials (currently 12 yards between clubs +/- 1 yard).