I don't know if I understood the entire project right, but here are some
notes.

There will be no problem to view a dynamic InfoPath form in Linux for read
only; you even don't need SharePoint portal server at this stage.

What you can do is the following:

You will need SharePoint services to view data from the database, like a
list of data, and each item in the list represents a form,, that is simple
for SharePoint, all what you need to do is create a web service that will
get the data from your database and format it as you want, drag it and drop
in SharePoint, and the data is there.

The rest is like a simple SharePoint list, you may improve it by using xslt

For the InfoPath side, create a form, connect it to the web service (in this
case the web service must be modified to return a tree structured schema in
order to build the form over it, and that is so painful, BizTalk 2004 can do
easily, but the problem there is this product was not designed originally to
work with dynamic database, not mentioning a large database, forget it if
you have more than 10 tables, that if you ever get it connected to the DB

But once you pass stage, design the form, add all the code you want, test
and publish the form as a form not as a library, just a simple xsn file.
(you don't want to publish it as a library because the form saves and reads
from the web service, the web service saves to the database, and SharePoint
already shows a list from that database, so you have the full loop)

Once the form is published, anyone who have Windows can use it for
read/write

For the people who have linux, just write a small asp page on the web
server, to find out if the click is coming from Windows or linux.

Extract the form files to a folder (all you need is the xsl file, and using
3 or 4 .net commands you can convert it to hml)

The form is dynamic, it receives its data as xml from the web service, and
.net is using the xsl to give you the html.

The final form will look very similar to the InfoPath once, but just read
only.

You can use this as a sample for transforming a form, the net is full will
samples too

http://livetechnologies.ca/Old%20Contents/InfoPath%20to%20HTML.zip

What you will realize, is that .net is capable of presenting the form just
like InfoPath.

But remember the following, whatever you try to do with infopath, if its out
of the normal, like a large form saving and loading to a database, you will
not find it easy at all, just search for my old postings on these message
boards, and you will get the idea :)

But anyway, the product is good, and as much as I hate it, it seams I can't
live without it :-)