Matthieu wrote (w. snips)...

What would be a nice metal equivalent of the KA6E or Foka 4?

I am asking because those ships are 40+ years old now and I am
concerned about the aging wood... Should I be concerned?

Peace of mind would seem to incompatible w. structural concern of any kind,
regardless of validity. (FWIW, I've never been able to talk myself into
flying wood ships. Wood I trust...but those glue joints are another mental
matter!)
- - - - - -

Is there any relevant metal alternative to those ships? I would also be
interested in any clues in terms of pricing.

I am a 5'6'' and 137 lbs pilot. What I love about those 2 ships (apart
of their outstanding behaviors and performances) are the narrow - low
cockpit and their light weight for soft-weak conditions flying. I am
flying out of Hope British Columbia.

snip
It is a Laister Nugget LP15. Do you know any other metal ships
comparable to the Laister Nugget?

You might research HP-14's, which would seem to meet your low wingloading &
low cost desires...and which are also flaps-only ships like the Nugget. All
are homebuilt/experimental save for the (very few) HP-14C's built by
Slingsby. I'd characterize the cockpit as OK for long lanky types, but
somewhat constricted for beamy sorts. Mine fit this 5'9", 140 lb pilot
nicely. Actually, the whole HP series is worth a look if you're OK w.
flaps. The -14 happened to be the last of Dick Schreder's 'purely riveted'
construction birds; later models tended toward bonded wing skins. All have
well-deserved (IMHO) reputations for structural integrity.

Have fun!

Regards,

Bob Whelan