I adore my 2 bassi Della Noce Pennese organetto. It's a 2 voice tremolo in G tuning, and weighs 2,2 kg. I attach a photo of the exact model I have, a beginners model, but it sounds great !
It's a diatonic with 3 extra buttons on a second row , with inversed diatonic notes, to make fast diatonic scale runs.
(if you want extra chromatic notes, one could ask an accordion repairer to change those 3 extra buttons ("le vocette") and replace the reedplates and reeds with chromatic notes. This way you could have 1,5 chromatic bisonoric accordion)
I think in the near future, I'm also going to buy a mini organetto (probably a Dino Baffetti art. 20):
http://baffetti-accordions.com/fisarmoniche/art-20/
This Dino Bafetti organetto is only 900 grams - 1 kg. The downside is, it's a 1 voice only (My standardsize Della Noce is a 2 voice, and I prefer the full tremolo sound of a 2 voices accordion).
I contacted Dino Bafetti by email to ask if they could make this mini organetto in a 2 voices version. Because I think it would only raise the weight with a couple of 100 grams.
The sound of this mini organetto is very strong and powerful outdoors, but a single voice instrument can sound rather sharp and too loud to play inside your home. Those mini boxes don't have cassottos to mute the sound or make it more mellow. They are meant to be played outdoors or at music festivals, parties, weddings, etc.
My Della Noce is a 2,5 octaves diatonic, but I don't really nead the low octave that much. The range of a mini organetto is sufficient to fool around and "fake" organetto playing. People actually think that I can play the organetto, all I do is "faking" and improvising, but I'm having a great time with it ! (I bought it in october 2019 in a music shop in Penne, close to Pescara, Italy)