[Kungsgeten]

First me and partner played a forcing pass system, where pass was 0-7 or 17+. To make this work we had a very nebolous 12-16 1C opening, and the other bids were 8-11. We quite enjoyed the 8-11 stuff, except opening 1S on 8-11 balanced when vul (1NT was 12-14). The 1C opening was a burden though. Right now we play a strong club structure instead (very similar to Moscito), but the club opening isn't quite as good as the forcing pass (because of all the interference). I had an idea of combining a forcing pass with Fantunes 2-openings, this was the first structure:

Pass - 0-7(8) / 17+ any
1C - 12-16 balanced or clubs
1D - 12-16, 4+ diamonds, unbalanced
1M - 12-16, 5+ major
1NT - 9-11
2X - 8-11, 5+ suit

The problems, as I see it, is that the 12-16 balanced range in 1C is hard to manage, especially in competition or if responder do not have a 4 card major (we were planning to play transfer responses, where opener responds 1NT with the upper range of the interval). Also the problem still exists that opening 1NT red with 9-11 is asking for trouble. Also opening hands with 5-4 majors at the two-level is probably a bad idea.

The new idea is to mix it up with the Moscito structure:

Pass - 0-7 any, 8-10 balanced or 17+ any
1C - 11-13 balanced / 8-11 both majors / 12-16 with 6+ clubs
1red - 12-16, transfer to major, may have longer minor suit (not 4432 or 4333)
1S - 12-16, 6+ diamonds or 9+ cards in the minors
1NT - 14-16 bal
2X - 8-11, 5+ suit. 2M denies the other major

The main problems here is that the weak interval of the pass opening may be to large, perhaps it will be a problem? The 1C opening may also look problematic, but I actually think it looks worse than it is. 6+ clubs 12-16 is rare (especially if you decide that it denies a 4+ major), but should do well in competition. 8-11 with both majors (at least 5-4) may be able to bid again at the two-level, especially if partner doubles. The 11-13 hand is the most common and the one partner will expect.

[PhilKing]

Make 1♣ clubs or balanced and 1♦ = diamonds or balanced, then you can split the ranges. Your 1♦ opening will still be tighter than most.

Within your original structure, put the 12-14 range through 1♦.

[Kungsgeten]

You mean something like:

Pass = 0-7(8) / 17+
1C = Clubs or 9-11 bal (perhaps switch 1NT and 1C depending on vul)
1D = Diamonds or 12-14 bal
1M = 5+ major
1N = 15-17
2X = 8-11, 5+

It is a posibility, even though I'm not too fond of two balanced oriented minor openings. The main downside here is what to do with 8-11 and 5-4 majors (have to open 2M with the longer I guess). If we put 9-10 balanced into the pass we could do something like this:

1C = Clubs or 11-13 bal
1D = Diamonds or 14-16 bal
1NT = 8-11, both majors

or (if we ignore the both majors problem)

1C = Clubs or 11-13 bal
1D = Diamonds
1NT = 14-16

[rbforster]

Assuming you want your 8-11 5+ unbalanced hands bidding a Fantunes style 2 bid (possibly excepting both majors), this leaves the one level to cover 2-3 balanced ranges and all the intermediate strength hands not strong enough for pass. Something simple would be:

p 0-8 or 17+
1♣ 12-17 bal , or clubs 12-16
......1♦ artificial and invitational, 10+
............1M 4M unbal with clubs, min 12-14
............1N 12-14 bal
............2♣ min just clubs 12-14
............2♦ artificial, 15-16 with clubs (Polish style)
............2M 4M with 15-17 balanced (stayman)
............2N 15-17 balanced no major
.......1M natural, 5-9 NF opposite weak NT
.......1N no 4M, 0-7 (no game interest even opposite strong NT)
.......2♣ 3+ no major, 8-9 (invite opposite strong NT)
.......2♦ 5+ no major, 8-9 (invite opposite strong NT)
1♦ 4+ unbal 12-16, including xx45
1M 5+, 8-16 with both majors, or 12-16 without
1N 9-11 bal

On one hand, the 9-11 NT is great for preempting. OTOH, its simpler to design a rebid structure after 1♣ if you had a split balanced range (9-11/15-17) with a standard weak 12-14 NT.