There is a little piece of software that give possibilities to run puredata as vst/vsti.
Is there a kind of similar project for linux, that could run puredata as a LADSPA plugin ?

Using Jack for audio and AlsaMIDI or OSC for control could work, more flexible than a plugin although more inconvenient if you need to work on something over more than one session.

that was just my question, i would like something that could be as usuable than reaktor as vsti with easy avaibality of save current work. The jack way is nice for experiments, but for some traditional way of compo work it is pure pain.

EnergyXT will be available in linux with the version 2 it would be a complete sequencer host, i hope there would be a way to add puredata kind of wrapper for made patch that will save with energyXT project. EnergyXT (non-free but cost near nothing) + PureDATA together would make me definitivly delete my win32 partition.

Agreed, it would be nice. It's possible to have multiple instances of pd each with unique PID so no problems with them messing with one another.
The subtlety is - how to map controls? I think Miller did an amazingly correct insight to separate the pd-gui from the daemon, but now what hapens when you wrap it to define your interface? I think that would need a lot of thought to do it right, because what you are wishing for sounds more like a wrap of the pd-gui into a plugin.
For pedestrian 2 in 2 out audio I guess no problem, but for complex synthesisers &c, well it loses a lot of richness that is really the point of puredata (for me imho)
If it could be done I'd most want to use them as processors in Ardour.
Right now I do pretty much what Claude is saying, Open one pd (my master fx processing rack) with multiple I/Os, then
I use jack to patch it all together. Ardour remembers its routing so that kinda saves as much state as I need as long as I don't want to radically change things between projects. But repatching stuff is fiddly as you have to change app windows back and forth between Ardour, qjackctl (the patcher), and PureData. Probably a useless 2c, but the idea is appealing.