I see that Hibernate Search requires Apache Lucene, and that there is a Lucene.NET in incubation according to the Apache site.

Will there be an all-.NET version of NHibernate Search, and if not is it possible that NHibernate Core will somehow use Hibernate Search?

I wasn't even aware of that, wow. This looks like a _really_ cool idea.

At the moment, this doesn't exist for NHibernate, the Lucene.net project is a fairly mature one, and it is used by many projects.
Without checking the code, I can pretty much say that it will not be possible to just use Hibernate Search.

About porting it, this will be done in the usual way.
Someone that wants it will port the functionality when it is needed.

I may (or may not) find use for this in my next project and port it, but that is a very cautious statement.

Okay, I took a look at the code, and it is a fairly big task.

It involves porting Hibernate Events to NHibernate, and I don't think that we will do that for 1.2

A partial solution may be to use an Interceptor to do the indexing directly, since that does exist in NH 1.2.

Interceptor + transaction.afterCompletion() if you have a similar concept should be enough to trigger the right operations.
You'll have to do some late initialization though, since you don't have access to the list of entities.

Many thanks for checking into it.

We're a crossplatform shop - I'm a .NET/J2EE architect and I'd like my respective leads able to justify using tools like this widely across our systems. As is common enough in such environments we have executive/senior management in favor of Java while the perform folks prefer a blend in the back to mid tier and .NET on the mid to outer. Anything we can do to get the best of both platforms is deeply appreciated.

Just to note, do not expect it shortly, I am very busy at the moment...

We don't. :-) Wish I had the time to contribute myself.