We should see rather significant sales increases with various major titles that are multi-port for the PS3. Generally speaking, the Japanese fanbase is going to defintately go with the PS3 version of every, and any multi-port title between X360 and PS3. Just like in the US, where most will go with the X360 over PS3 - both have their strong fanbase in each country, and have a better brand image and are more likely to sell more in their repsective home countries.
Having said this though, the X360 will see significant growth with the titles you named. RE5, DMC4,and various other titles will boost X360 sales by considerable numbers, like the PS3. The % increase might even match PS3 numbers, but obviously, the PS3 is typically selling at a 4:1 ratio over the 360.
A quick survey of the X360/PS3 multi-port titles thus far:
Ridge Racer Series (6 & 7):
Playstation: 139,185
Xbox 360: 72,830
Both titles were released during Launch Periods, and are certainly comparible. We see that the PS3 version sold at nearly a 2:1 ratio (or should end up with exactly 2:1)
Armored Core 4
Playstation: 84,976
Xbox 360: 23,252
The Playstation version was released during PS3's launch, whereas AC4 for X360 launched in March, 4 months after the PS3 launch. The sales ratio is 3.65:1 Neither version is charting as far as I know (top 200).
Enchanted Arm
Playstation: 36,202
Xbox 360: 22,890
A reverse of AC4. The X360 version was exclusive, and launched last January, whereas the PS3 version launched in Febuary (or so). Despite the huge lead, and exclusivity claims, the X360 version sold quite a bit worse. The sales ratio here is 1.58:1 Obviously another example of the X360 having the lead, definitive version and selling worse in Japan.
Call of Duty 3
Playstation: 22,097
Xbox 360: 18,125
An interesting comparison, as both launched kind of close to eachother. Here, the X360 version had about a 3 month lead on the PS3 version. This is one of the few games that were given truely equal footing. As we can see, the PS3 version is, as always, doing better. COD3 is still charting for the PS3, and should wind up with 27,500 units. The current ratio is 1.21:1 currently, but will probably end up with an LTD of 1.5:1 or more. Intrestingly enough, the attach ratio for the X360 version is, like many other games, quite a bit higher.
Rainbow Six Vegas
Playstation: 17,669
Xbox 360: 21,656
RSV launched 2 weeks ago for the PS3, and has already reached just about 80% of the X360s LTD totals. Rather impressive, but like many other games, not a blowout. PS3 RSV totals should reach COD3 numbers, and be around 27.5k. However, like COD3, the tier ratios on the X360 are quite a bit better.
Conclusion: The PS3 games obviously sell more. However, this is almost entirely due to the PS3s larger install base. At any point, each of these games, except for AC4, the PS3 had atleast a 2:1 hardware attach rate versus the X360. It can be concluded that this is the driving factor behind the sales, and no other extrapolation is really needed.