Just to get things straight, it seems like most in-house positions are for corporate lawyers (?) who are keep a general practice (?). So this means that junior lawyers should keep that in mind when they are determining their practice area (if they are thinking to eventually exit private practice to go in-house) ... What do you think the in-house opportunities are for junior lawyers in commercial real estate? (Less than general corporate lawyers, I am assuming). Would they be working for a REIT or what type of company? And what work would they be doing?
Many in-house positions are for corporate lawyers, but not all of them. If we're limiting ourselves to in-house lawyers with private companies (e.g.: not federal government), then you need to look at the types of things an institutional client might want to do.
Of the top of my head, real estate, trademarks/patents, employment/labour, and corporate are all things that a big enough institutional client might want. Outside of pure litigators often not being in house (with a few exceptions), I don't think your general assumption is a good one.
I don't know real estate very well, but I know many companies which are sufficiently large want lawyers for their acquisitions of real property, so real estate is an area where junior lawyers find some opportunity. Someone else might be better suited to speak to it.