GG5, etc.

Dictionaries either combine 架ける with 掛ける/懸ける or keep them apart. The combiners include ルミナス (Daijirin ignores it totally). We've gone with the majority and have it as a separate entry, but include the "sometimes written ..". Our "sometimes written .." note implies it is is not quite kosher; otherwise we'd have it in the headword area, or have a single merged entry, so I wouldn't support cluttering the entry with even more qualifications.
That 電線を架ける really only applies to wires strung between points - you wouldn't say it if it was along the ground.

See below.

"かける" is certainly an odd concept. Maybe it is not a horror. Maybe it is a benefit, in so far that one seems to be able to activate virtually any conceptual notion by the addition of the term "かける". But, I prefer the horror concept; as far as the beginner is concerned.

In Kenkyusha's entry it shows: "かける　掛[懸,架]ける hang; suspend; etc..

It was that entry, together with the "small-screen" issue which encouraged me to make the submission.

You also have the following enty:-
電線を架ける 【でんせんをかける】 (exp,v1) to lay a wire

I wounder if that is to lay a wire (on the ground, etc.) or to suspend it between two points (even though it ends op laying on the ground, so to speak).

Coming back to the point that a cross-reference is inappropriate as it's not the "correct" form, I wonder if in the above entry one should state that fact, e.g., " (sometimes written [inappropriatey as] 掛ける)". Then a cross-reference would clearly be unnecessary.

I don't think an xref to 掛ける is appropriate as it's not the "correct" form. You can only go so far in constructing a display which avoid misunderstanding. かける is a horror, and the sooner a beginner learns about its issues the better.

When I searched for "かける", the above was on the screen. It was on the screen because it was at the bottom of the list of entries. This is often a "small-screen" problem when the main entry for "かける" cannot be readily seen; and the novice does not know that the main entry exists. I know this cannot be avoided. However, when you have given a reference point, i.e., "sometimes written 掛ける", it may help to have a cross-link to the target referred to. So, in this case, the novice is likely to click on the link because it is there and discover the really important entry for "かける". Without the link, the novice may regard "掛ける" as simply and alternative to "架ける"; as could be the case with many kanji, with the alternative being of no great importance other than the fact that it is sometimes used instead of the main entry.

Entry created