I hear what you're saying. There is one company with a set out there like that. They split the single length concept into two lengths so that your long irons are longer and your short irons are shorter but all fall into one of two lengths.
Have you ever tried one length for the 5,6,7, and 8 irons?
This new set(not available yet but soon) starts at the 5 iron and goes the the PW. A 37 inch(or so) PW is hard to wrap your head around at first but when you get used to it I've found it extremely beneficial for a high handicapper for me. The PW in a traditional set is too short for me.
Ever since I stumbled upon the concept online I haven't been able to figure out why clubs have been made in 1/2" increments for generations. The reviews from people who have given the SL concept a shot has been overwhelmingly positive. I am just happy that there is going to be another option out there. It looks like the ones produced from valuegolf.com are going to have a thinner sole which the rest of the SL irons out on the market today(new or old) have a wide sole.