Company form seems rather irrelevant. Unhindered EU wide commerce is much more important. See e.g. the mess caused by WEEE regulations. Selling EU wide has become a very expensive proposition.

To go work as a self employed person in Belgium you first need (before you leave your previous country) to make a Limosa declaration. Failure to do so, can result in heavy penalties for you and any company you do work for. So any company you want to work for will insist on having a limosa.

http://www.limosa.be/

To make a Limosa declaration as self employed in Belgium you'll need your Belgian vat number, you do have one of those don't you? No?

To apply for your vat number you need a 'Bedrijfsbeheer' (a 125 hour night school qualification available in Dutch, French and German that shows you understand basic bookkeeping).

http://nl.wikipedia.org/wiki/Bedrijfsbeheer_(attest)

You do speak Dutch or French don't you? No?

Well you can take the equivalent official course in another country, if such a thing existed. Or you could take a year off to learn the language which is not exactly practical.

Or you can prove 6 years of continuous self employment in your field in the last 10 years, or 3 years of continuous self employment plus 3 years of related secondary level study.

So 125 *hours* of Belgian study requires 3 *years* of EU study to be considered equivalent....

You can see how easy it is for countries to block foreign workers by administrative hurdles. I'm giving Belgium as an example, but most of the older EU countries play similar games. They know they're no competitive, they know the businesses are setting up in newer states like Spain, Czech republic and Poland, and they're trying to hang on to what they have by administrative trickery.

So for self employed people too, you have to take away the ability of countries to preemptively block trade in services.

Note that 2005/36/EC doesn't fix this, because it failed to define these little 'mini' qualifications (like the Bedrijfsbeheer) used to block self employed people from trading.

http://europa.eu/scadplus/leg/en/cha/c11065.htm

If anything, that creates a whole new bunch of loopholes to work with.

When scanning down the headlines, I read this one as

‘EC pans proposed EU biz structure’...

I need more sleep.