A good chunk of NDP MPs and other notables have started lining up behind candidates, and it might be worthwhile to note who is supporting who:
Fmr NDP Leader Ed Broadbent
Fmr Sask. Premier Roy Romanow
Gatineau MP Francoise Boivin (QC)
BC MLA Dawn Black
BC MLA John Horgan
Fmr BC NDP Leader Joy MacPhail
BC MLA Michelle Mungall
Sask MLA Pat Atkinson
Vaudreuil-Solanges MP Jamie Nicholls (QC)
Trois-Rivieres MP Robert Aubin (QC)
Jonqiuere-Alma MP Claude Patry (QC)
Montmagmy-L'Islet-Kamouraska-Riviere-de-Loup MP Francois Lapointe (QC)
Longueuil-Pierre-Boucher MP Pierre Nantel (QC)
Laurentides-Labelle MP Marc-Andre Morin (QC)
Saint-Jean MP Tarik Brahmi (QC)
Louis-Saint-Laurent MP Alexandrine Latendresse (QC)
Windsor West MP Brian Masse (ON)
Scarborough-Rouge River MP Rathika Sitsabaiesan (ON)
Burnaby-Douglas MP Kennedy Stewart (BC)
Notre-Dame-de-Grace MP Isabelle Morin (QC)
Abitibi-Temiscamingue MP Christine Moore
Now, there's a couple things to take from this list.
First, Peter Julian and Tom Mulcair are more than likely running. Given the amount of support they're receiving, it seems unlikely they won't, and especially so in Julian's case (after all, Mulcair has reasons for not running).
Second, not a heck of a lot of the NDP caucus seems to be rushing to Topp's side. Meanwhile, Mulcair is soaking up most of the newly elected Quebec MPs, while Julian could make the case that his support is a little national in nature (sure, only four endorsers, but it works). Saganash gains the support of his next-door neighbor.
Third, note how Topp is getting heavy support from some influential BC Dippers - Dawn Black, Joy MacPhail, John Horgan, who in BC politics are known names. What's so special about BC, you ask? It contains the plurality of NDP memberships as it currently stands, outpacing even Ontario, and far outstripping Quebec. This is a pretty deliberate action on Topp's part. He knows where the members are, so he's going to sow up that province's support now, rather than later.
Finally - could you classify Topp's support as pretty establishment-heavy? I would. He gains the support of heavyweights like Broadbent and Romanow, and I wouldn't be surprised if, as the race progresses, we see further establishment, or old-guard, support of Topp.
So, what would make Mulcair and Julian?
Mulcair is easy to quantify - he's Quebec's favourite son. The only slight counterweight that Topp has is Gatineau MP Francoise Boivin, who since 2007ish has been the alternate big-name in the NDP's Quebec wing. But even so, Topp is clearly not getting the support from Quebec MPs that one would expect he needs to show that, hey, I can appeal to Quebecers, just like Jack did. Why this is would be an interesting question to pose to the new MPs (do they feel loyalty to Mulcair, or will he just be the best candidate for Quebec?).
Julian seems something like Stephane Dion - he has a fairly random collection of MPs supporting him. I know, it's early, but I bet that Julian will not get as many BC supporters (as Dion failed to get many Quebec supporters); he'll pick up support in Ontario (as Dion did), and he'll gain the support of a couple of provincial leaders (as Dion did). He seems like a the middle choice between Topp and Mulcair - as Dion (or Kennedy) seemed the middle choice between Rae and Ignatieff.
And yes, unlike others, I generally dismiss Saganash as a candidate. It's not that I don't think he can't pull off an unexpected surge, like Obama, but I don't think he's anywhere near as charismatic, nor does he have anything like a wedge issue Obama had (re: Iraq War) to push out other candidates. Plus, Mulcair will probably ensure he'll keep Saganash down as a threat.
(Hopefully, no one was actually expecting a map - it's just a phrase, though if you want a map, readers, you shall have it)